The normal role-based access control (RBAC) model decouples users and permissions through roles,and different software systems have different implementation syteles.The paper proposes an engine model which can configure the RBAC management systems flexibly.It is a configuration tool to generate different RBAC management systems which meet different users’ requirements. The practice proves that the engine model can improve the efficiency and quality of software development. The role-based access control model decouples users and permissions through roles in order to simplify authorized operations and safety management[1]. Many literatures[2-6] discuss the RBAC model from different aspects. Some literatures[2-3] add new elements to the normal RBAC model,and these models are unidimensional according to the manipulated resources.For example, the NIST RBAC reference model [2] extends and standardize the RBAC96 [1] model reasonably.Some literatures[4-5] introduce time property to RBAC model and they are two-dimensional models according to the manipulated resources.Literature[6] furtherly add visual data muster to RBAC model and proposes a three-dimensional access control model. All of these models only discuss access control model theoretically,and different role-based access control modules in software systems have different instantiation sytles.For example, a RBAC module in one software system can not meet the access control requirements in another system because different RBAC modules have different table fields in order to realize certain requirements. This paper proposes a flexible role-based access control engine which can configure the RBAC module for different systmes according to each customer’s requirement.The engine is a configuration tool and it can realize various RBAC modules which have different table fields in database.The paper is organized as follows.Section I introduces the basic concepts of the NIST RBAC model;Seciton II details the description of RBAC engine model and gives the configuration steps using this engine to generate RBAC instances,and at last section III gives an example and concludes the paper.